Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the behavioral burden, and it discloses normalization to monthly, automatic T1-T4 tiering, computed outputs, and explicit default/disclosure behavior for missing frequency and omitted investments. It does not explicitly state whether the calculation is persisted or has side effects, which matters given sibling tools like save_calculation.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with the core action and result, then covers usage, data-quality expectations, and edge-case defaults. Every sentence adds operational information, and there is no filler or repetition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be fully explained, and the schema already documents all six parameters in detail. The description adds important data-integrity and default-handling context, though it could state more explicitly that the tool is a pure calculation and does not itself save the result.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with rich per-field descriptions already documenting income, expenses, frequency, investments, projection horizon, and return assumptions. The description adds some meaning, such as treating omitted investments as zero and disclosing frequency defaults, but most parameter semantics remain supplied by the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource: 'Builds a monthly budget.' It also enumerates normalization, tiering, and returned metrics, and scopes the tool to a household's actual monthly net income and expense items, which distinguishes it from the tax, pension, mortgage, and investment siblings.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It explicitly says 'Use to summarize a household's actual monthly net income and expense items' and instructs the agent to ask for the actual expense ledger or item amounts and never fabricate expenses. It does not name a when-not condition or an explicit alternative sibling, but no sibling tool clearly overlaps with this budgeting purpose.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.